You create in encore you menus. Button 1 links to videoA, Button2 Video B. Button 3 you want to link to a outside source, say a webpage, pdf.... You create a button, then link it to a blank timeline.

The next step is to create a DVD Folder from Encore. Then open eDVD, after picking your video.ts files, it will have a pulldown for each button in your menu. Select the button, then just follow the pulldowns to establish what you want to do.

After that all you do is burn the DVD and voila, DVD-Rom. The only drawback is that you need Interactive Player to access the DVD rom features. For computers that don't have this, it will install upon being put in the DVD drive, but some people get all freaky about stuff like that.